Presently, a Group III nitride compound semiconductor device is generally grown on a non-conductive sapphire substrate, and comprises an n-electrode and a p-electrode both of which are formed at a semiconductor device layer side. Here, a lateral type of Group III nitride compound semiconductor device has a thin-film light-transparent electrode made of, for example, an alloyed gold (Au) and cobalt (Co) on the surface of a p-type layer, and outputs lights from the side on which the electrode is formed. The Au/Co thin-film light-transparent electrode, however, has poor light-transparency of about 60%, and extract efficiency of light is not adequate.
Alternatively, indium tin oxide (ITO) may be used to form the light-transparent electrode on the Group III nitride compound semiconductor device.
[Patent Document 1] Japanese Patent No. 3394488
[Patent Document 2] Japanese Patent Laid-open No. 2003-17748